The Truong Son Fold Belt,located at the northeastern margin of the Indochina Block,is considered to be tectonically linked to the subduction of the Paleotethys Ocean and subsequent collision.Sepon is one of the most i...The Truong Son Fold Belt,located at the northeastern margin of the Indochina Block,is considered to be tectonically linked to the subduction of the Paleotethys Ocean and subsequent collision.Sepon is one of the most important super large deposits of the Truong Son Fold Belt.Our LA-ICP-MS zircon U-Pb dating results show that granodiorite porphyry samples from the Sepon deposit have ages of 302.1-4-2.9 Ma, which is a crucial phase for magmatic-tectonical activities from the Late Carboniferous to Early Permian and has avital influence on the mineralization of copper and gold.Zircon from granodiorite porphyry yields εHf (t)values of 4.32 to 9.64,and TDM2 has an average age of 914 Ma,suggesting that the source of the granodiorite porphyry in the region were mainly mantle components but underwent mixing and contamination of crust materials.The Ce^4+/Ce^3+ value of zircon in the granodiorite porphyry varys greatly from 2.4 to 1438.29,which shows magma mixing might occur.Considering the characteristics of trace elements in the zircon and the whole rock geochemical characteristics of intrusion rocks as well as the characteristics of regional volcanic-sedimentary association,it is indicated that the tectonic setting may be the continental arc environment.The Sepon Au-Cu deposit is derived from emplacement of calc-alkaline intermediate-acid magma with coming from deep sources in the subduction process of the Paleotethys Ocean,forming porphyry Mo-Cu,skam Cu-Au mineralization and a hydrothermal sedimentary-hosted Au mineralization in the wall rocks.展开更多
1.Objective The Sepon Au-Cu deposit(Fig.1)is the largest polymetal deposit ever discovered in Laos,of which the resources of gold and copper is 102 t(Au:1.6 g/t)and 1.96×10^6 t(TCu:2%)(Zhu HP et al.,2013)respecti...1.Objective The Sepon Au-Cu deposit(Fig.1)is the largest polymetal deposit ever discovered in Laos,of which the resources of gold and copper is 102 t(Au:1.6 g/t)and 1.96×10^6 t(TCu:2%)(Zhu HP et al.,2013)respectively.Sepon Au-Cu deposit is one of the most important super large deposits of the Truong Son Fold Belt.The Truong Son Fold Belt,located at the northeastern margin of the Indo-China terrane,is considered to be tectonically linked to the subduction of the Paleotethys Ocean and subsequent collision.The granodiorite porphyry samples from the Sepon deposit belong to I-type calc-alkaline series and tectonic settings are continental arc environment(Cromie PW,2010).LA-ICP MS zircon U-Pb dating results show that granodiorite porphyry samples from the Sepon deposit have ages of 302.1±2.9 Ma.The in situ zirconεHf(t)values range from+4.32 to+9.64,and TDM2(Hf)has an average age of 914 Ma(Wang XY et al.,2018).In this study,the authors present new in situ zircon oxygen isotopic data to identify the source of the magma.展开更多
基金the National Science Foundation of China (41373036, 41002027)the Geological Survey of China Geological Survey Project (121201103000150006,121201066307).
文摘The Truong Son Fold Belt,located at the northeastern margin of the Indochina Block,is considered to be tectonically linked to the subduction of the Paleotethys Ocean and subsequent collision.Sepon is one of the most important super large deposits of the Truong Son Fold Belt.Our LA-ICP-MS zircon U-Pb dating results show that granodiorite porphyry samples from the Sepon deposit have ages of 302.1-4-2.9 Ma, which is a crucial phase for magmatic-tectonical activities from the Late Carboniferous to Early Permian and has avital influence on the mineralization of copper and gold.Zircon from granodiorite porphyry yields εHf (t)values of 4.32 to 9.64,and TDM2 has an average age of 914 Ma,suggesting that the source of the granodiorite porphyry in the region were mainly mantle components but underwent mixing and contamination of crust materials.The Ce^4+/Ce^3+ value of zircon in the granodiorite porphyry varys greatly from 2.4 to 1438.29,which shows magma mixing might occur.Considering the characteristics of trace elements in the zircon and the whole rock geochemical characteristics of intrusion rocks as well as the characteristics of regional volcanic-sedimentary association,it is indicated that the tectonic setting may be the continental arc environment.The Sepon Au-Cu deposit is derived from emplacement of calc-alkaline intermediate-acid magma with coming from deep sources in the subduction process of the Paleotethys Ocean,forming porphyry Mo-Cu,skam Cu-Au mineralization and a hydrothermal sedimentary-hosted Au mineralization in the wall rocks.
基金This work was supported by the National Science Foundation of China(41373036,41002027)the geological survey project of China Geological Survey(DD20190437).
文摘1.Objective The Sepon Au-Cu deposit(Fig.1)is the largest polymetal deposit ever discovered in Laos,of which the resources of gold and copper is 102 t(Au:1.6 g/t)and 1.96×10^6 t(TCu:2%)(Zhu HP et al.,2013)respectively.Sepon Au-Cu deposit is one of the most important super large deposits of the Truong Son Fold Belt.The Truong Son Fold Belt,located at the northeastern margin of the Indo-China terrane,is considered to be tectonically linked to the subduction of the Paleotethys Ocean and subsequent collision.The granodiorite porphyry samples from the Sepon deposit belong to I-type calc-alkaline series and tectonic settings are continental arc environment(Cromie PW,2010).LA-ICP MS zircon U-Pb dating results show that granodiorite porphyry samples from the Sepon deposit have ages of 302.1±2.9 Ma.The in situ zirconεHf(t)values range from+4.32 to+9.64,and TDM2(Hf)has an average age of 914 Ma(Wang XY et al.,2018).In this study,the authors present new in situ zircon oxygen isotopic data to identify the source of the magma.
